The present invention generally relates to a sorter and more particularly, to a sorting apparatus of a "floating" spiral cam type to be used in copying arrangements such as a copying machine, printer, reader printer or the like for sorting or collating copy paper sheets discharged therefrom.
It is to be noted here that the terms "sorting" or "collating" used throughout the present specification and claims are intended to mean that "sorting" is a mode in which, in the case where, for example, three original documents are each copied for ten sheets, the copied sheets taken from the three original documents are distributed into respective bins, one sheet by one sheet, while "collating" is a mode in which copied sheets taken from one original document are all distributed into one bin.
It should be noted that the term "sorting apparatus of a floating spiral cam type" means a sorting apparatus in which each of the spiral cams having a spiral groove is arranged to be vertically movable along a rotary shaft, while it is rotated together with said rotary shaft upon rotation of the latter as in an example to be explained hereinafter.
The sorting apparatus of the above described type has conventionally been disclosed, for example, in U.S. Pat. No. 4,478,406 entitled "Apparatus For Sorting Photocopies". As shown in FIGS. 1 and 2, the known sorting apparatus S of a floating spiral cam type is releasably coupled to a copying machine (not shown) so as to receive copy paper sheets discharged through a pair of discharge rollers (not shown) provided at a discharge portion of the copying machine via guide plates g, and includes a pair of feed-in rollers R.sub.1 and R.sub.2 disposed in fixed positions, another pair of discharge rollers R.sub.3 and R.sub.4 arranged to be movable in unison with spiral cams C arc guided through slots L.sub.1 formed in the frame of the apparatus S, an upper transport belt V.sub.1 movably passed around the rollers R.sub.1 and R.sub.3, a lower transport belt V.sub.2 also movably passed around the rollers R.sub.2 and R.sub.4, a plurality of trays or bins B provided vertically at proper intervals for receiving copy paper sheets therein as specifically disclosed in said U.S. Pat. No. 4,478,046. Each of the bins B properly spaced from each other has a pair of trunnions T provided on a lip portion P of said bin to extend laterally from each side thereof, and said trunnions T are slidably received in a pair or slots L.sub.2 formed in the frame of the sorting apparatus S for vertical movements so that the interval between the bins B at the side of the discharge rollers R.sub.3 and R.sub.4 may be enlarged to correspond to the positions of said rollers R.sub.3 and R.sub.4.
As shown in FIG. 2, a pair of rotary shafts Cs to be driven by a drive mechanism M are provided at the outer side of the frame of the sorting apparatus, and on each of said shafts Cs, the spiral cam C is fitted so as to be slidable along the shaft Cs in the vertical direction, but rotatable as one unit together with said shaft. (The sorting apparatus having the spiral cam moving in the above described manner is sometimes referred to as the sorting apparatus of a "floating" spiral cam type.) Each of the sprial cams C is formed, on its outer peripheral face, with a spiral groove Cg of a generally U-shaped cross section for 360.degree. in the rotational angle, i.e., by one revolution so as to slidably receive the trunnion T therein. Accordingly, when the spiral cams C are rotated by one revolution, the trunnions T engage the spiral cams C by one set for displacement by one pitch.
Referring also to FIGS. 3(a) through 3(e), changes of the state with time of the bins B down to the fourth stage from the top, and the spiral cams C will be described hereinafter.
It is to be noted that in the following description, explanation will be given with reference to the spiral cam C and trunnion T only at one side for brevity, and that for differentiation of the bins B, trunnions T, etc. at respective stages, numerals .circle.1 , .circle.2 , .circle.3 and .circle.4 are affixed thereto in the numerical order from the top to the bottom. In FIGS. 3(a) through 3(e), the deviation in the vertical direction between the respective portions in the figures shows displacement in the relative level with respect to the frame of the sorting apparatus S.
In the first place, FIG. 3(a) shows the state where the sorting of copy paper sheets into the bin B-(3) is completed, and the rotary shaft Cs is to be driven for rotation in the direction of an arrow A so as to effect the sorting for the bin B-(4). Meanwhile, the sprial cam C is prevented from descending by the trunnion T-(3), with the bin B-(2) raised by one pitch of the spiral groove Cg, and the rotational angle at this time is assumed to be at 0.degree.. FIG. 3(b) shows the state where the spiral cam C has been rotated by 1/4 turn, and the spiral groove Cg leads the bin B-(3) upwardly, while the trunnion T-(3) receives the weight of the bin B-(3) and the bins B-(1) and B-(2) located thereabove descend with the spiral cam C until it reaches the trunnion T-4. FIG. 3(c) represents the state where the sprial cam C has been rotated by 1/2 turn, and the spiral cam C rotates and is prevented from descending by the trunnion T-(4), thereby raising only the bin B-(3). FIG. 3(d) shows the state where the spiral cam C has effected a 3/4 rotation, with the bin B-(3) raised to contact the bin B-(2). FIG. 3(e) denotes the state where the spiral cam C has rotated one revolution, in which the spiral cam C rotates from the state in FIG. 3(d) to raise the bin B-(3) along with the bins B-(1) and B-(2) located thereabove until the trunnion T-(3) is ultimately disengaged from the spiral groove Cg so as to return to the state before one rotation (rotational angle at 0.degree.). Thus, the sorting for the bin B-(4) is effected in this state, and the similar functioning as described so far is intermittently effected at each sorting.
As described so far, in the known sorting apparatus S, the bins B (i.e., bins B-(1) and B-(2) in the above example) located at the upper stages above the bin B immediately after completion of the sorting, effect unnecessary vertical movement during rotation of the spiral cams C in spite of the fact that their positions are not altered before and after said rotation. Therefore, not only load torque of the spiral cam C is increased, but problems such as improper alignment of copy paper sheets on the bin B due to vibrations, etc. are invited, and such tendency becomes particularly conspicuous when high speed copying is to be effected.